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Construction Holdbacks in Ontario: The Complete 2026 Guide for Contractors

10% of every invoice held for months. Here is how holdbacks work under the Ontario Construction Act, how they affect HST, and how to track them without spreadsheet chaos.

NorthBoost Team•May 2026•9 min read
Ontario-specific. The statutes, rates and regulators cited here are Ontario's. NorthBoost works across Canada, and the equivalent rules differ by province — check your own before relying on the numbers.
Quick facts
Statutory holdback rate10%
Basic lien period60 days
Annual release ruleNew in 2026
Typical exposure$200,000+

If you have been in construction in Ontario for more than a year, you know the pain: you complete the work, send the invoice, and then wait because 10% is being held back until the lien period expires.

For small and mid-sized contractors, holdbacks are one of the biggest drivers of cash-flow stress. This guide explains how holdbacks work, where the HST traps are, and what a practical tracking system should look like.

A holdback is a mandatory retention of 10% of each progress payment and it applies across the payment chain. It exists to protect lien rights under the Ontario Construction Act.

The 2026 Ontario Construction Act amendments introduced mandatory annual holdback release. That improves predictability on long-running projects, but only if your contracts and internal process actually reflect the new rule.

The HST trap is simple but brutal: HST on holdbacks is not always due when cash is received. Timing depends on release or lien-period expiry. Contractors who do not reserve for that get surprised by CRA remittances.

The practical operating system is straightforward: project-level holdback tracking, a holdback aging report, and reminders tied to substantial performance dates. The problem is not the theory; it is lack of consistent execution.

Delays in holdback release often come from documentation gaps rather than actual disputes. Signed deficiency lists, statutory declarations, lien waivers, and clean project closeout paperwork make a real difference.

The contractors who manage this well treat holdback recovery as a process, not a memory exercise. They know exactly how much is locked up, where it sits, and when it should come free.